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    User name R. Michaels

    Log entry time 11:07:46 on June29,2004

    Entry number 127365

    This entry is a followup to: 127362

    keyword=online background results

    Here are some "near-online" results for the background
    rates. Note, I do not normalize by the target thickness
    ratio "xt". (For Helium target xt was 0.25).

    ratio HAPPEX run 2527 (Alum) to 2526 (prod)
    Beam current was 29 uA for most of run 2526, but was 35 uA
    from event 10400 to 13800, so I cut on that.
    For run 2527 beam was 35 uA.
    So the ratio at 35 uA :
    det1 = 1826 / 44000 = 4.2 % (multiply this by "xt")
    det2 = 2031 / 43400 = 4.7 %
    det3 = 1923 / 43500 = 4.4 %
    det4 = 3100 / 44000 = 7.0 % ... anomaly !

    Compare to spectrometer DAQ:
    Rates for T2 and T4, normalized to current (extrap. to 2 uA).
    There is a fairly big error here due to accuracy of current
    at low current. But this error might improve later.
    Right arm (T2), ratio = 4.7 +/- 1.5 % (multiply this by "xt")
    Left arm (T4), ratio = 4.0 +/- 1.5 %
    These are consistent with HAPPEX DAQ except for det4 anomaly.

    FWIW, the raw detector, tracks, look ok. Can see the dummy walls
    in Z distribution at target (run 1204).